The word "stuck-upness," which refers to someone who acts superior or arrogant, can be described using a variety of synonyms. Such as, haughtiness, conceit, pretentiousness, snobbishness, superiority, and arrogance. These words all suggest an inflated sense of one's own importance or ability, leading to a patronizing or dismissive attitude towards others. Other synonyms include showing off, snootiness, hubris, overconfidence, and disdain. In short, a person with stuck-upness is someone who looks down on others and believes they are better than everyone else. So, if you encounter such a person, you can appropriately describe them using any of the above-suggested synonyms.